* [CVE-2026-92484][MODERATE REGULAR] cxl/region: Fix use-after-free in find_pos_and_ways() error path [ Upstream
@ 2026-09-18 3:52 21% AL-KERNEL
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From: AL-KERNEL @ 2026-09-18 3:52 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-92484
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: cxl/region: Fix use-after-free in find_pos_and_ways() error path [ Upstream
Commit: 68edf359b0b45cad2654510c1ca257079b241aa5
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=68edf359b0b45cad2654510c1ca257079b241aa5
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92484
Analysis date: Thu, 17 Sep 2026 23:52:51 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO
Summary:
No one-sentence report phrase was found.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-92484 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92484
The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.
This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.
The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.
Published priority for this report: MODERATE REGULAR
Manual review required: NO
A detailed explanation of the methodology and priority rules is included
at the end of this message.
======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================
CVE-2026-92484 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-92484 CHECK WITH IMPACT FROM ORIG NN LOW Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H';*CWE-416;CWE-825;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'A use after free can occur in find_pos_and_ways when the CXL region error path drops the final reference to a switch decoder device and then accesses its name for an error message. The stale device access can cause a kernel fault or panic and results primarily in local denial of service. For the CVSS the PR:H is selected because triggering the affected CXL region configuration path normally requires administrative CXL device and region management privileges. The issue is not network reachable. The paranoid score includes C:L because stale device data could potentially be read into a kernel diagnostic log. No integrity impact or privilege escalation primitive is demonstrated by this error reporting use after free.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) SKIP CVE-2026-92484 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: url YES NO NO unknown MAYBE ERRORPATH UAF INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 - - checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=1
PrimitiveClass=CLASS_B
RealUAF=YES
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 1
* Conservative score: 1
* Raw paranoid score: 1
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate**::
No UAF floor is applied because host-admin-equivalent CXL region management is required. No paranoid point is added because the patch establishes only a stale diagnostic dereference, not controlled reuse, a write primitive, or a usable disclosure path.
2. Signal breakdown
* +2 Real UAF / lifetime violation. `put_device(dev)` can drop the final reference and free the switch-decoder device before `dev_name(dev)` is evaluated in the error message.
* +1 Realistic kernel crash or DoS. Dereferencing a freed `struct device` during error reporting can cause an Oops or panic.
* -2 Host-admin-equivalent privilege requirement. Reaching CXL region creation and decoder-management paths requires administrative control of host CXL device and region configuration.
* No controlled reclaim or replacement is demonstrated.
* No arbitrary or directed kernel write is demonstrated.
* No repeated release or refcount mutation exists. The patch moves the single `put_device(dev)` after the diagnostic access, so there is no second `put_device`, `kref_put`, or equivalent mutation through the dangling reference.
* Structured stale-object leverage is not awarded. Although `struct device` is structured, the stale use is limited to `dev_name()` in an error-reporting path.
* Confidentiality is not awarded. The error path may theoretically format stale data, but no attacker-readable diagnostic-log path or meaningful disclosure is established.
* Integrity and privilege escalation are not awarded. No post-free write, callback dispatch, object substitution, or security-boundary bypass is shown.
* Remote reachability is not established.
* No additional rare-hardware penalty is applied. CXL hardware is a prerequisite, but the available evidence does not establish a separate attacker-access restriction beyond host CXL administrative control.
3. Reachability analysis
The evaluated attacker is a host administrator managing CXL regions and decoder topology. The affected function is reached while processing CXL region configuration and an error condition involving a missing target-list entry.
Host-admin-equivalent control is required because CXL region configuration operates through host device-management interfaces and affects host-owned CXL hardware state. There is no evidence that an ordinary local user, container user, or namespace-scoped capability holder can complete the full region-management sequence.
NamespaceScopedPrivilege is `NO` because CXL memory devices, ports, switch decoders, and region configuration are host hardware resources rather than network-namespace-scoped objects. No network packet, remote protocol, firmware-controlled remote input, or guest-triggerable path is established.
A CXL-capable host and an invalid or incomplete target-list configuration are prerequisites. The bug is an ordered error-path sequence, not a race requiring timing manipulation.
4. Primitive and severity interpretation
The exact primitive is a real use-after-free: a device reference is dropped before `dev_name()` reads the same device object. If that `put_device()` is the final reference, the decoder can be freed before the diagnostic formatting operation.
This is a constrained `CLASS_B` lifetime bug. The stale object is a `struct device`, but the demonstrated use is shallow and limited to an error-reporting call rather than active decoder processing, pointer traversal, callback invocation, object replacement, or a second lifetime mutation.
This is not a repeated-release/refcount case:
A. The existing vulnerable behavior is an ordinary stale diagnostic dereference after a possible final `put_device()`.
B. There is no later second `put_device()`, `release()`, `kref_put()`, or refcount-changing operation on the same dangling reference.
The demonstrated consequence is local kernel fault or denial of service. A stronger consequence such as information disclosure, integrity loss, controlled reclaim, or privilege escalation remains speculative and is not supported by the supplied patch.
`ImportantCandidate=NO` is appropriate because the error-path UAF has no demonstrated meaningful reuse, post-free mutation, controlled data influence, or security-boundary consequence. `AutoDowngradeAllowed=YES` is appropriate because this is a constrained crash-capable UAF with host-administrator gating and no unresolved active corruption primitive beyond the stale dereference.
Likely operational severity is ordinary Moderate or lower priority in environments without CXL hardware or without administrative CXL region management exposure. It should still be patched through normal kernel maintenance because it is a confirmed UAF capable of causing a host kernel failure.
5. One-sentence report phrase
A CXL region error path can dereference a switch decoder device after dropping its final reference, causing a local kernel crash or denial of service during privileged CXL region management.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
The patch establishes a real UAF and potential host crash, but the stale use is restricted to error logging after a host-admin-controlled CXL configuration failure and does not demonstrate reusable memory corruption or privilege-escalation leverage.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: cxl/region: Fix use-after-free in find_pos_and_ways() error path [ Upstream
Commit: 68edf359b0b45cad2654510c1ca257079b241aa5
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=68edf359b0b45cad2654510c1ca257079b241aa5
Changed files:
drivers/cxl/core/region.c
Diff excerpt:
Not included in this email. See the upstream URL for the full patch.
Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=68edf359b0b45cad2654510c1ca257079b241aa5
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-92484 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-92484
The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.
The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.
This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.
The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.
Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:
Conservative CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
The Best / paranoid CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H
The Best / paranoid CVSS score: 4.7
The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.
CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.
A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.
Conservative ActionableScore: unknown
Paranoid ActionableScore: 1
The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.
For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:
ActionableScore below 5 -> MODERATE REGULAR
ActionableScore 5 or more -> MODERATE 7.0
The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.
There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).
KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.
AL-KERNEL base severity for this report: MODERATE
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): MODERATE REGULAR
These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).
Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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